Analyses of a whole-genome inter-clade recombination map of hepatitis delta virus suggest a host polymerase-driven and viral RNA structure-promoted template-switching mechanism for viral RNA recombination.

The genome of hepatitis delta virus (HDV) is a 1.7-kb single-stranded circular RNA that folds into an unbranched rod-like structure and has ribozyme activity. HDV redirects host RNA polymerase(s) (RNAP) to perform viral RNA-directed RNA transcription.

HER2 testing in paired biopsy and excision specimens of gastric cancer: the reliability of the scoring system and the clinicopathological factors relevant to discordance.

Background: Inclusion of trastuzumab in chemotherapy regimens is advantageous for patients with advanced or metastatic gastric cancer who overexpress HER2. Therefore, accurate assessment of HER2 status in tumor tissue is critical when weighing treatment options.

Methods: We examined HER2 expression in 180 paired endoscopic biopsy and surgical excision specimens of gastric cancers via immunohistochemistry (IHC).

Detection of hepatitis delta virus recombinants in cultured cells co-transfected with cloned genotypes I and IIb DNA sequences.

It was reported previously that hepatitis delta virus (HDV), the only animal virus in which replication is performed by cellular RNA polymerase(s), undergoes RNA recombination. However, the previous RNA transfection system was somewhat limited in terms of practical application. Cultured cells were transfected with plasmids expressing replication-competent genotypes I and IIb HDV genomic RNAs to develop a better system for studying the fundamental aspects of HDV RNA recombination and HDV-related RNA species were examined using restriction fragment length polymorphisms and sequence analysis of cloned RT-PCR products.